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US 5,691,466 AGranted
Liquid-sensing apparatus and method
AssigneeJTL Systems Limited
InventorsJohn Michael Walmsley Lawrence, John Frederick Harkness
Life of this patent
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AssigneeJTL Systems Limited
InventorsJohn Michael Walmsley Lawrence, John Frederick Harkness
Estimating the term…
A device for detecting the presence of liquid in a flow of gas has a heated temperature sensor mounted on a heated member in thermal contact with the gas and an unheated temperature sensor in thermal contact with the gas, but thermally isolated from the heated temperature sensor. Liquid in the gas flow evaporates by absorbing heat from the heated member and therefore reduces the temperature of the heated temperature sensor. The reduction in temperature is used to detect the presence of liquid. The device is suitable for detecting liquid at the output of an evaporator in a heat transfer system, and may be used as part of a control system which reduces the flow of refrigerant through the evaporator when liquid is detected at the output, so avoiding damage caused by liquid entering the compressor of the heat transfer system.
A method of sensing the presence of liquid in a flow of gas which is contained by a wall having a thermally conductive portion, the method comprising disposing first and second temperature sensors in thermal contact with respective first and second thermally conductive members in contact with the gas flow and mounted on said wall, the first temperature sensor having a heating means associated therewith, the first thermally conductive member being substantially thermally isolated from said thermally conductive portion of said wall and from the second thermally conductive member and monitoring a difference in the temperatures sensed by the two temperature sensors.
A liquid-sensing apparatus for sensing the presence of liquid in a flow of gas which is contained by a wall having a thermally conductive portion, comprising first and second temperature sensors mounted on respective first and second thermally conductive members adapted to be in thermal contact with the gas flow and mounted or mountable on said wall, a heating means arranged to provide heat to the first thermally conductive member and isolating means for thermally isolating the first thermally conductive member from the second thermally conductive member and from said thermally conductive portion of said wall.
A liquid-sensing apparatus for sensing the presence of liquid in a flow of gas, comprising a tube through which, in use, the gas flows, a first temperature sensor in thermal contact with a first portion of the tube wall, a heating means arranged to provide heat to said first portion, a second temperature sensor in thermal contact with a second portion of the tube wall, and at least one aperture formed in the tube wall between the first and second portions.
A liquid-sensing apparatus for sensing the presence of liquid in a flow of gas, comprising a first temperature sensor, a first housing member in thermal contact with the first temperature sensor, a heating means arranged to provide heat to the first housing member, a second temperature sensor and a second housing member in thermal contact with the second temperature sensor, the first and second housing members being disposed end-to-end with a thermally insulative element sandwiched in between so as thermally to isolate said housing members from each other.
A liquid-sensing apparatus for sensing the presence of liquid in a flow of gas, comprising first and second temperature sensors mounted on respective first and second thermally conductive members adapted to be in thermal contact with the gas flow, and a heating means arranged to provide heat to said first thermally conductive member, the first and second members being disposed within a thermally insulating moulding such that the first and second members are thermally isolated from each other and the thermally insulating moulding being located within a tube through which, in use, the gas flows, such that the first member is thermally isolated from the tube wall.
Dependencies are inferred from the claim text.